Week 8 Worm Gear Challenge

Aim: perform a transient structural analysis on a worm gear assembly.

Procedure:

Open transient structural module in ANSYS workbench
open engineering data and select required material, in this case we will use structural steel , and mechanical property of structural steel is given below

Density : 7.85e-06 kg/mm³

Isotropic Secant Coefficient of Thermal Expansion : 1.2e-05 1/°C

Young's Modulus: 2e+05 MPa

Poisson's Ratio: 0.3

Bulk Modulus: 1.6667e+05 MPa

Shear Modulus: 76923 MPa

Tensile Yield strength : 250 MPa

Compressive Yield strength : 250 MPa

Tensile Ultimate strength : 460 MPa

Isotropic Thermal Conductivity : 0.0605 W/mm·°C

Specific Heat Constant Pressure: 4.34e+05 mJ/kg·°C

Isotropic Resistivity: 0.00017 ohm-mm

Isotropic Relative Permeability: 10000

close the engineering data tab and upload geometry and edit same in space claim

now we will cut the gear split option and remove the half parts as shown below

Now close the spaceclaim and udate geometry in model , open mechanical model using edit option

expand the geometry tab and rename the component as Gear and worm as shown in below

as by default both the component have assign with structural steel , we will proceed for connection

we make frictionless contact between gear and worm

deployed a revolute joint to gear ,
connection type : body to ground
type : revolute

gound to body revolute joint has given to worm as shown below

for analysis setting we use 15 step
for 1st step
Auto time stepping : on
define by : time
initial time step: 0.2 s
Minimum time step : 0.2 s
maximum time step : 0.5
solver type : program controll
weak spring : program controll
large deflection : on
output controll , set all parameter yes except contact miscellenous as NO

for step 2 to 15
Auto time stepping : on
define by : time
carry over time step: on
minimum time step: 0.2 s
maximum time step: 0.5 s
solver type: program controll
weak spring : program controll
Large deflection : on
output controll , set all parameter yes except contact miscellenous as NO

now deployed a rotational joint to worm
magnitude will be define by tubular data
details of tubular data given below

for mesh , we will use default generated mesh

now list out required output parameter and run for simulation

Picture:

total deformation

Equivalent elastic strain

Equivalent stress

Contact pressure:

Force reaction at contact region

Result :

	Minimum	Maximum	Average
Total deformation	1.1096 mm	7.261 mm	4.5391 mm
Equivalent elastic strain	2.9602e-012 mm/mm	5.307e-003 mm/mm	2.0324e-004 mm/mm
Equivalent stress	3.6773e-007 MPa	997.98 MPa	31.554 MPa
Contact pressure	0. MPa	1302. MPa	48.139 MPa

	X-axis	Y-axis		Z-axis	Total
Force reaction at contact region	-5.3156 N		-1739.2 N	0.76792 N	1739.2 N

COnclusion :

1. The transient structural analysis on a worm gear assembly was carried out successfully.
   2. The maximum value of total deformation is 7.261 mm.
   3. The maximum value of equivalent stress is developed in the teeth of the worm wheel i.e., 997.98 MPa.
   4. The maximum value of Equivalent Elastic Strain is developed in the teeth of the worm wheel i.e., 5.307e-003.
   5. The maximum equivalent stress and strain is developed in the teeth of the worm wheel, which will eventually lead to failure hence, it is recommended to change the material of the teeth of worm wheel